1. Field of the Invention
The invention relates to a cosmetic brush, in particular a mascara brush or a brush for dying hair, comprising a bristle portion with a base body and a plurality of bristles that stick out from the base body and serve for the application of a cosmetic product.
2. Background Art
Such a cosmetic brush and a corresponding injection molding process are for example described in DE 25 59 273 A1. The base body that is described there is hollow and forms one piece with the bristles. A thermoplastic, elastically deformable plastic material is used, such as an elastically resilient polyethylene. This makes the bristles soft and elastic, thus guaranteeing a very pleasant feeling when applying the cosmetic product. Plastic materials that are currently used in such injection molding processes usually have a Shore hardness A in the range of between 60 and 95, the Shore hardness being determined according to DIN EN ISO 868. Moreover, the density of relatively soft polyolefins that are popularly used in this field is determined according to DIN EN ISO 1183 and is typically in the range of between 0.91 g/cm3 and 0.94 g/cm3. The use of such flexible plastic materials however also involves several restrictions as far as economically feasible designs of the cosmetic brush are concerned. In addition to that, the chemical compatibility of these relatively soft and elastic materials such as polyethylene and polypropylene with the cosmetic product to be applied is often unsatisfactory.
Along with conventional mascara brushes in which a plurality of bristles are held in place between a wire portion that is bent in the shape of a hairpin by twisting the wire portion, an increasing number of brushes that are available on the market is now produced by injection molding as described above. The bristles of these brushes are also produced by injection molding, i.e. they are not bristles in the conventional sense. For the sake of simplicity, however, this term will be retained throughout the text.